Definitely compare widths between companies as they do vary. Many years ago I tried out quilts and went with a regular width per company recommendation which was 52". I'm on the small and vertically challenged side (5'4" and between 145lbs-150lbs) and went back to bags as that quilt was difficult to keep out drafts....it was a bad experience that could have been prevented.
Fast forward and after realizing I was using my bag roughly as a quilt decided to research and try again.
I researched Nunatak, Katabatic, Enlightened Equipment to name a few and wound up going with El Coyote as it seemed to have a great feature set, was more than adequately filled, and their regular at 56" is wider than many other companies regulars (Katabatic is 52" and Enlightened Equipment is 54")....plus El Coyote is very comparably priced with minimal wait time from order to door.
After receiving it in less than a week from purchase (even with it made to order) I couldn't be happier with the over all quality of construction, attention to detail, and customer service Brian at El Coyote provided, as my numerous questions I'm sure felt endless.
The pad attachment system is as good as any and very easy to use, the zippered footbox is longer than others at 24" which allows to close it up more thoroughly in the legs if wanted....plus with the width it is easy to keep tucked preventing any drafts.
Additionally, for side sleepers vertical baffles in the torso and hip region keep the down in place as horizontal baffles, especially without overfill, can have down migration causing cold spots.